Fire crews work the crash site of Asiana Flight 214 at San Francisco International Airport on July 6, 2013. / John Green, Bay Area News Group via AP

by Bart Jansen and Nancy Trejos, USA TODAY

by Bart Jansen and Nancy Trejos, USA TODAY

As officials try to piece together what led to the Asiana Airlines Flight 214 crash, investigators from the National Transportation Safety Board will analyze air-traffic control records, weather, aircraft maintenance and the crew's actions from data recorders aboard the plane.

A team of federal safety investigators headed for San Francisco on Saturday, where they will focus on flight operations, human performance, survival factors and the aircraft, including its power plants. The investigator in charge will be Bill English.

"Everything is on the table at this point," said Deborah Hersman, chairman of the NTSB and the member who is traveling to the accident site.

Hersman said it is too early to say whether the crash resulted from pilot error.

"We have to gather the facts before we reach any conclusions," she said.

Kevin Hiatt, CEO of the Flight Safety Foundation, said based on past crashes investigators will likely provide daily briefings for a week with factual accounts of what is found and where they efforts are being focused.

Any conclusions about what caused the crash are likely months or years away, Hiatt said.

Boeing's 777 has been a relatively reliable aircraft, according to safety experts.

The crash occurred on a day with clear skies, but the crew apparently knew they had a problem as the plane approached the airport. A recording of the airport's air-traffic controllers provided by FlightAware.com, a website that tracks flights, had the controllers assuring the crew that "emergency vehicles are responding. We have everyone on their way."

Chesley Sullenberger, the retired commercial pilot who landed the "Miracle on the Hudson" flight in New York, told KCBS-TV that runway construction at the San Francisco airport may be a factor the NTSB will examine. Sullenberger, a CBS News aviation and safety analyst, said the construction mandated by the Federal Aviation Administration is designed to move the runway further from the seawall near where the jet struck ground.

"It's too early to say if (the construction) is going to be a factor in this case, but it certainly is something they'd be looking at," Sullenberger said.

Kevin Darcy, an aviation safety expert and retired chief investigator for Boeing, says it is unusual for the tail of an aircraft to come apart.

"I just haven't seen anything like that for years and years and years," he says. "There's no way of knowing if this is the same circumstance, but the last time I saw a situation where the tail came off like that on landing was during the flight testing from a DC-9."

He says investigators will have much more data to work with than they have had in previous accidents.

"They'll look at the human aspect and the flight control system themselves," Darcy says. "They're not going to draw any conclusions until they have a chance to look at all those things."

John Hansman, an aerospace professor at Massachusetts Institute of Technology and director of the International Center for Air Transportation, said the 777 has been a reliable aircraft.

"We don't know what's going on in this case, but at this point there's nothing I've seen that points to a problem with the airplane," Hansman said.